 (pretty/install-pretty-logging)
 (pretty/install-uncaught-exception-handler)
 
-(def conf (edn/read-string (slurp "conf.edn")))
+(def conf-filepath (get (System/getenv) "CONF_PATH" "conf.edn"))
+(def conf (edn/read-string (slurp conf-filepath)))
 
 (defonce switchboard (sb/component :backend/switchboard))
 
 (defn restart!
-  "Starts (or restarts) a system built out of the specified subsystems. The switchboard will
-  then fire up subsystems according to the blueprint maps, which are in passed in the second
-  position of the :cmd/init-comp vectors. These subsystems are then wired to provide the
-  communication paths required by the application.
-  The system can be restarted on the REPL. For example, say we modify the
-  birdwatch.percolator.percolator namespace. Then, we can reload it:
+  "Starts (or restarts) a system built out of the specified subsystems. The
+   switchboard will then fire up subsystems according to the blueprint maps,
+   which are in passed in the second position of the :cmd/init-comp vectors.
+   These subsystems are then wired to provide the communication paths required
+   by the application.
+   The system can be restarted on the REPL. For example, say we modify the
+   birdwatch.percolator.percolator namespace. Then, we can reload it:
 
     (require '[birdwatch.percolator.percolator :as perc] :reload)
 
-  Then, calling this function again will restart the system while maintaining the state of
-  the individual subsystems."
+   Then, calling this function again will restart the system while maintaining
+   the state of the individual subsystems."
   []
   (sb/send-mult-cmd
     switchboard
     [[:cmd/init-comp
-      #{(sente/cmp-map :backend/ws-cmp markup/sente-map)    ; WebSockets component
-        (sched/cmp-map :backend/scheduler-cmp)              ; Scheduler component
-        (pc/cmp-map :backend/persistence-cmp conf)          ; Persistence-related component
-        (redis/cmp-map :backend/interop-cmp (:redis conf))  ; Redis PubSub interop between JVMs
-        (perc/cmp-map :backend/percolator-cmp conf)         ; Matching tweets with searches
-        (metrics/cmp-map :backend/metrics-cmp)}]            ; Metrics and stats
+      #{(sente/cmp-map :backend/ws-cmp markup/sente-map)
+        (sched/cmp-map :backend/scheduler-cmp)
+        (pc/cmp-map :backend/persistence-cmp conf)
+        (redis/cmp-map :backend/interop-cmp (:redis conf))
+        (perc/cmp-map :backend/percolator-cmp conf)
+        (metrics/cmp-map :backend/metrics-cmp)}]
 
      [:cmd/route {:from #{:backend/scheduler-cmp :backend/ws-cmp}
                   :to   :backend/persistence-cmp}]
 
-     [:cmd/route {:from #{:backend/persistence-cmp :backend/percolator-cmp :backend/metrics-cmp}
+     [:cmd/route {:from #{:backend/persistence-cmp
+                          :backend/percolator-cmp
+                          :backend/metrics-cmp}
                   :to   :backend/ws-cmp}]
 
-     [:cmd/route {:from #{:backend/interop-cmp :backend/ws-cmp :backend/scheduler-cmp}
+     [:cmd/route {:from #{:backend/interop-cmp
+                          :backend/ws-cmp
+                          :backend/scheduler-cmp}
                   :to   :backend/percolator-cmp}]
 
      [:cmd/observe-state {:from :backend/ws-cmp

                                          :message [:schedule/count-users]
                                          :repeat  true}]}]
     [:cmd/send {:to  :backend/scheduler-cmp
                 :msg [:cmd/schedule-new {:timeout 5000
                                          :message (with-meta [:cmd/get-jvm-stats]
                                                              {:sente-uid :broadcast})
                                          :repeat  true}]}]]))

(defn -main
  "Starts the application from command line. Also saves and logs process ID. The system that is
   fired up when start! is called proceeds in core.async's thread pool. Since we don't want the
   application to exit when just because the current thread is out of work, we just put it
   to sleep."
  [& args]
  (pid/save (:pidfile-name conf))
  (pid/delete-on-shutdown! (:pidfile-name conf))

(ns birdwatch.main
  "This is the main namespace of the server side of BirdWatch. It is written in
   Clojure and makes use of the systems-toolbox library
   (https://github.com/matthiasn/BirdWatch) for building and wiring components.
   Below, a switchboard is created, which is a specialized component for
   wiring components together so that messages flow through a system as desired."

  (:require [matthiasn.birdwatch-specs.specs]
